Scalable network apparatus for content based switching or validation acceleration

ABSTRACT

A network apparatus is provided that may include one or more security accelerators. The network apparatus also includes a plurality of network units cascaded together. According to one embodiment, the plurality of network units comprise a plurality of content based message directors, each to route or direct received messages to one of a plurality of application servers based upon the application data in the message. According to another embodiment, the plurality of network units comprise a plurality of validation accelerators, each validation accelerator to validate at least a portion of a message before outputting the message.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation (and claims the benefit of priorityunder 35 U.S.C. §120) of U.S. patent application Ser. No. 14/494,410filed on Sep. 23, 2014 and entitled SCALABLE NETWORK APPARATUS FORCONTENT BASED SWITCHING OR VALIDATION ACCELERATION, which application isa divisional of U.S. patent application Ser. No. 13/706,286 filed onDec. 5, 2012, now issued as U.S. Pat. No. 8,862,773, which applicationis a continuation U.S. patent application Ser. No. 12/350,675 filed onJan. 8, 2009, now issued as U.S. Pat. No. 8,346,969, which applicationis a divisional of U.S. patent application Ser. No. 09/566,800 filed onMay 8, 2000, now issued as U.S. Pat. No. 7,512,711, which application isa continuation-in-part of U.S. patent application Ser. No. 09/549,041,filed on Apr. 13, 2000, now issued as U.S. Pat. No. 6,732,175, and isalso a continuation-in-part of U.S. patent application Ser. No.09/562,104 filed on May 1, 2000, now issued as U.S. Pat. No. 7,146,422.The disclosures of the prior applications are considered part of and arehereby incorporated by reference in their entirety in the disclosure ofthis application.

FIELD

The invention generally relates to computers and computer networks andin particular to a scalable network apparatus which may be cascadedtogether to accommodate increased traffic.

BACKGROUND

While increasingly more successful in their roles as store and forwarddata systems, computer networks such as the Internet are experiencingtremendous growth as transaction-based, mission critical businessapplications, Web site owners, and business servers are overwhelmed byexplosive traffic growth. The traditional approach is to buy moreservers and network bandwidth. There is typically no distinction betweenlevels of service, but rather a first-in first-out (FIFO) best effortsapproach has been the default. However, this has resulted in unevenperformance and undifferentiated service. Clearly, there is a need for atechnique to allow service providers to intelligently offer differentservices and different levels of service depending on the circumstances.

Systems are available that allow messages to be routed based uponheaders or header information. For example, in Hypertext TransferProtocol (HTTP), a Post request method includes a request line, a header(or one or more headers) and a body. The request line includes a pointerto a requested resource or program to process the message, such as aUniversal Resource Identifier (URI) or Universal Resource Locator (URL).The HTTP header may also include the type of message, the length of thebody, and the date. There are systems that parse or examine the URL(i.e., the request line) and/or the HTTP header, and then route themessage to a destination node based on the URL and/or header. One suchsystem is described in “The Advantages of F5's HTTP Header LoadBalancing Over Single-Point URL Parsing Solutions.” However, thisapproach is very limited as switching decisions are based only on theHTTP header and/or URL.

XML, or eXtensible Markup Language v. 1.0 was adopted by the World WideWeb Consortium (W3C) on Feb. 10, 1998. XML provides a structured syntaxfor data exchange. XML is a markup language, like HTML. Most markuplanguages, like HTML, are fixed markup languages. That is, the fixedmarkup languages (including HTML) include a set of fixed tags forcrafting a document. On the other hand, XML does not define a fixed setof tags, but rather, only defines a syntax or structured format throughwhich users can define their own set of XML tags. There presently are anumber of XML based languages which define their own set of tags usingthe XML syntax. XML has the further advantage because the actual data isseparated from the presentation of the data, in contrast with HTML whichcombines these two items. As a result, XML has the potential to become astandard by which most computers, servers and applications will exchangeor communicate data.

Another system, known as BizTalk™, improves slightly on the URL parsingtechnique by providing a system that is compatible with XML-basedmessages. As described in “BizTalk Framework 1.0a Independent DocumentSpecification,” Microsoft Corp., Jan. 7, 2000, BizTalk defines aspecific set of tags (or BizTags) within a message that are used tospecify business document handling (p. 7). A Biztalk server usesinformation contained in the Biztags to determine the correcttransport-specific destination address(es). (pp. 9, 11). However, thetags used to mark up business transaction information within the messagebody are determined by the individual implementation. Theseimplementation-specific tags (provided in the content or businesstransaction information of the message body) are not considered BizTags(p. 11). The BizTalk system is very limited because it can route orswitch messages based only upon header or introductory information,based upon the fixed set of the BizTalk tags. The BizTalk system doesnot make decisions or route/switch messages based upon the actualcontent of the application data or business information (e.g., businesstransaction information) within the message body. Moreover, performingsuch processing at an application server can inhibit or decrease thenumber of documents or transactions that can be processed by theapplication server

In addition, the XML standard only requires that a received document bechecked to confirm that it meets the basic syntax and format of XML(i.e., determine whether the document is “well formed”). In addition,the XML standard also allows a document to be validated, which is a morerigorous check to determine if the structure or grammar of the XMLdocument complies with structure required by the particular XML basedlanguage. Although not required by the XML specification, manyapplication servers or other processing nodes that process XML documentsinclude a validating XML processor (or a validating XML parser) to checkthe XML application data for validity against a validation template. Asa result, the burden of performing document validation can alsosignificantly decrease the number of documents or transactions that canbe processed by the application server or processing node.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and a better understanding of the present invention willbecome apparent from the following detailed description of exemplaryembodiments and the claims when read in connection with the accompanyingdrawings, all forming a part of the disclosure of this invention. Whilethe foregoing and following written and illustrated disclosure focuseson disclosing example embodiments of the invention, it should be clearlyunderstood that the same is by way of illustration and example only andis not limited thereto. The spirit and scope of the present invention islimited only by the terms of the appended claims.

The following represents brief descriptions of the drawings, wherein:

FIG. 1 is a block diagram of a network system according to an exampleembodiment.

FIG. 2 is a flow chart illustrating an operation of content basedmessage director according to an example embodiment.

FIG. 3 is a block diagram illustrating a director according to anexample embodiment.

FIG. 4 is a block diagram illustrating a traffic manager according toanother example embodiment.

FIG. 5 is a block diagram illustrating another example operatingenvironment for a content based message director according to an exampleembodiment.

FIG. 6 is a block diagram illustrating a network system according toanother example embodiment.

FIG. 7 is a diagram illustrating an example message according to anexample embodiment.

FIG. 8 is a flow chart illustrating an example operation of a validationaccelerator according to an example embodiment.

FIG. 9 is a block diagram illustrating a network apparatus according toanother example embodiment.

FIG. 10 is a block diagram illustrating an example scalable networkapparatus including multiple validation accelerators according to anexample embodiment.

FIG. 11 is a block diagram illustrating an example scalable networkapparatus including multiple content based message directors accordingto an example embodiment.

DETAILED DESCRIPTION I. Content Based Switching

Referring to the Figures in which like numerals indicate like elements,FIG. 1 is a block diagram of a network system according to an exampleembodiment. As shown in FIG. 1, a variety of clients may be coupled orconnected to a data center 135 via a network, such as the Internet 130.The clients, for example, may include a server 110 that includes anapplication program 112, a computer 120 (such as a personal computer orlaptop) that may include a web browser 122 and a wireless device 132,such as a personal digital assistant (PDA) or a wireless (or cellular)telephone. Wireless device 132 may be coupled to the Internet 130 or toa data center 135 via communications links 134 and 136, respectively.Links 134 and 136 each may include one or more of a wireless link (e.g.,cellular or other link) or a wireline link. Each of the clients,including server 110, computer 120 and device 132 can send and receivemessages over the Internet 130 and may use a variety of differentprotocols or transports.

The data center 135 is provided for sending, receiving and processing awide variety of messages, requests, business transactions, purchaseorders, stock quotes or stock trades, and other information. The datacenter 135 includes several processing nodes (e.g., servers), includingserver 150, server 160 and server 170 for handling the various orders,business transactions and other requests. The different servers in datacenter 135 may be allocated to provide different services, or evendifferent levels of services. According to an example embodiment, theclients and the data center 135 exchange business transactioninformation or other information by sending and receiving XML messages(data provided in XML or in a XML based language), or messages basedupon another type of structured syntax for data interchange.

The various servers (e.g., servers 150, 160 and 170) are coupled to atraffic manager 140 via a switch 165. Traffic manager 140 may perform avariety of functions relating to the management of traffic, includingload balancing (e.g., balancing the load of incoming messages orrequests across the available servers according to some policy, such asround-robin, least number of connections, or other load balancingtechnique).

Referring to the clients again in FIG. 1, application program 112 may bea business program or a program for managing inventory, orders or otherbusiness transactions. For example, application program 112 mayautomatically and electronically detect that inventory has decreasedbelow a threshold value and then automatically generate and send apurchase order to a supplier's server at data center 135 to request ashipment of additional supplies or inventory. Thus, server 110 mayinitiate, for example, a business-to-business (B2B) transaction bysending an electronic order to the supplier's remote server located atdata center 135.

As a another example, web browser 122 may request web pages, businessinformation or other information from a remote server (e.g., located atdata center 135). Web browser 122, may also send or post purchaseorders, business transactions or other business information to a remoteserver, which may be located at data center 135. Wireless device 132 mayreceive information or data related to purchase orders, businesstransactions, web pages, stock quotes, game scores and the like from oneor more remote servers (such as servers located at data center 135).

According to an embodiment, the server 110, computer 120 and wirelessdevice 132 each may communicate or interchange data with one or moreremote servers (e.g., servers 150, 160 and 170) by sending and receivingXML data (i.e., application data that is encoded or formatted accordingto the XML standard or according to one or more XML based languages).

According to an example embodiment, the traffic manager 140 includes acontent based message director 145 to direct or switch messages to aselected server based upon the content of application data, such asbusiness transaction information (which may be provided as XML data).Traffic manager 140 and/or message director 145 may be software,hardware or a combination of both, and may even be provided on or aspart of a network processor. It should be noted that director 145 mayoperate by itself, or as part of a larger network apparatus, such aspart of a traffic manager 140.

According to an example embodiment, because of the advantages of XML,application data can advantageously exchanged between the servers ofdata center 135 and one or more clients or computing nodes by sendingand receiving messages that include application data that is encoded orformatted according to the XML standard. Therefore, according to anembodiment, director 145 may be a XML director because it directs (orroutes/switches) the incoming message to a particular server based uponthe XML data in the message. The XML data preferably complies with theformat or syntax required by the XML standard. A document that uses tagformats (e.g., start tags, end tags) and other syntax (e.g., to markupdata) that complies with the XML standard is considered to be a“well-formed” XML document.

Therefore, in an exemplary embodiment, content based message director145 is a XML director. However, it should be understood that director145 can direct or switch messages having basically any type ofstructured syntax, including any type of markup language.

An advantageous aspect of the embodiment of the traffic manager 140 anddirector 145 shown in FIG. 1 is that the traffic manager 140 and thedirector 145 are located in front of the one or more application serversor processing nodes. By locating the traffic manager 140 and director145 in a computer, server or computing system in front of the processingnodes or servers (as shown in FIG. 1) (e.g., coupled between the network130 and the servers), the traffic management functionality and thefunctionality of the director 145 can be off-loaded from an applicationserver to a separate and/or dedicated network apparatus or networksystem. This can advantageously relieve the processing nodes orapplication servers from this additional processing overhead.

FIG. 2 is a flow chart illustrating an operation of content basedmessage director according to an example embodiment. At block 210, thedirector 145 receives a message. The message may be sent over anytransport or protocol(s), such as Transmission Control Protocol (TCP),File Transfer Protocol (FTP), Simple Mail Transfer Protocol (SMTP),Wireless Application Protocol (WAP, which may be used to send andreceive information with wireless devices), Hypertext Transfer Protocol(HTTP), etc. The general teachings and the operation of the inventionare not dependent upon any particular transport or protocol, but ratherare transport-independent.

A HTTP Post is an example of a message. The format for an HTTP Postmessage (or HTTP request) may be presented as:

request-line (the URL); identifies a program for processing the messageheaders (0 or more) <blank line> body (the application data or the XMLdata; only for a POST)

Here's an example:

POST www;acme.com/purchasing/order.cgi HTTP/1.1 Content-Type: text/xmlContent-Length: 1230 User-Agent: Cern-Line Mode/2.15 Date: 3/27/00 <XML>   <From>intel.com</From>    <To>bookstore.com</To>    <PurchaseBook>      <ISBN>02013798233</ISBN>       <PurchaseAmount>98</PurchaseAmount>    </PurchaseBook> </XML>

In this example, the URL (or request line) is provided in a request lineto identify a program or application to process the message. Severalheader lines (Content-type, Content-length, date, etc.) make up an HTTPheader. The application data is provided after the HTTP header, and inthis example is provided as XML data. A start tag <XML>, and </XML>, anend tag, identify the start and end, respectively, of the applicationdata (or XML data). This XML application data is also referred to as aXML document. The XML document includes markup characters (or tags)which describe data, and data characters. As an example, a “To” elementof the above XML document is written as: <To>bookstore.com</To>.Where<To> is a start Tag and </To> is an end tag, which are markupcharacters because they describe the XML data characters(bookstore.com). The business transaction information describes thebusiness transaction (To, From, items purchased, purchase amount,quantity, etc.), and is not included in the URL, the HTTP header, or anyother header (e.g., IP header, TCP header) of the envelope used forsending the message.

While the prior art performed switching based on the request line or URLand/or the HTTP header, the present invention is directed to a techniqueto perform switching at a network apparatus based upon the applicationdata, such as XML data (which includes business transactioninformation).

In this example message, the business transaction information providedwithin the application data as XML data relates to the transaction ordescribes the transaction, including, for example, what kind of businesstransaction (a purchase order or to purchase a book), who it is from andwho it is to, an ISBN number to identify the goods to be purchased andthe amount of the purchase (PurchaseAmount). These are merely examplesof the types of business transaction information in a message upon whichthe director 145 can analyze and make routing or switching decisions forthe message.

At block 215 of FIG. 2, the director 145 (FIG. 1) parses all or part ofthe application data (the XML data in this example) and can check toensure that the XML document or application data is well formed (i.e.,checks to make sure at least a portion of the XML document meets theso-called well-formedness constraints or requirements in the XMLspecification or standard). Parsing generally refers to the process ofcategorizing the characters or XML data that make up the XML document aseither markup (e.g., <To>) or character data (e.g., bookstore.com).

At block 220 of FIG. 2, the application data or XML data (includingmarkup characters and/or character data) is then compared to one or moreconfiguration patterns or queries (which may be stored in the director145) to determine if there is a match. According to an embodiment, theconfiguration patterns may be dynamically changed or updated by a useror by a program or application. For example, a program may detect thefailure of one or more servers and/or detect the response time ofservers, and then update the configuration pattern to account for thesechanges in the network (e.g., redirect certain messages from busyservers to servers which are less busy, or from servers which havefailed to the available servers).

At block 225, if there is a match between the content of the applicationdata (e.g., the business transaction information which may be providedas XML data) of a message and a configuration pattern or query, then thedirector 145 directs or switches the message to the corresponding server(or processing node) in the data center (e.g., directed to the specificserver as indicated by the configuration pattern). If there are multiplematches, the director 145 can just direct the message based to the firstmatch, or a load balancing policy can be used to balance messages amonga group of servers. If there is no match, the message can be directed toa default server or can be blocked. Alternatively, the configurationpattern can also identify a certain pattern for which a message shouldbe blocked from being forwarded. In this respect, the director 145 mayalso act as a filter to selectively pass or forward some messages whileblocking others, based upon the application data.

For example, the director 145 may be configured to direct or switchmessages based on the following configuration patterns or queries:

Server IP address Port XML pattern S1 (e.g., 150) 10.1.1.1 80 To =bookstore.com S2 (e.g., 160) 10.1.1.2 80 To = stockquote.com S3 (e.g.,170) 10.1.1.3 80 To = computerstore.com

Based on the above configuration patterns, the director 145 would directa message to server S1 (having the IP address 10.1.1.1 and port 80) ifthe data for the To element of the business transaction information isbookstore.com. The message will be directed to server S2 (having an IPaddress 10.1.1.2 and port 80) if the data for the To element of thebusiness transaction information is stockquote.com. And, the director145 will direct any messages to server S3 if the data for the To elementof the business transaction information is computerstore.com.

This advantageously allows different types of services (or differentlevels of service) to be provided for messages based on the content ofthe application data (such as the business transaction information) inthe message. In this example, server S1 may be allocated to handlepurchase orders for books sent to bookstore.com. Server S2 may beallocated to process requests for real-time stock quotes, while serverS3 may be allocated to process purchase orders for computers sent tocomputerstore.com.

There are many examples where content based switching based upon thecontent of the application data or business transaction information canbe used to offer different or differentiated services or even differentor differentiated levels of services. As another example, the director145 may be configured to direct or switch messages based on thefollowing configuration patterns or queries:

Server IP address Port XML pattern S1 (e.g., 150) 10.1.1.1 80PurchaseAmount < $100 S2 (e.g., 160) 10.1.1.2 80 $100 < PurchaseAmount <$1000 S3 (e.g., 170) 10.1.1.3 80 $1000 < PurchaseAmount S4 (not shown)10.1.1.4 80 $1000 < PurchaseAmount

In this example, messages for purchase orders are sent to server S1 ifthe purchase amount is less than $100; messages for purchase orders aresent to S2 if the purchase amount is less than $1000 and more than $100;and for the high dollar purchases, the messages for purchase orders forpurchases greater than $1000 can be sent to either of two servers. Inthis fashion, the director 145 (FIG. 1) can direct or route receivedmessages based on the content of the application data or businesstransaction information in the message. This allows web sites orelectronic-businesses (e-businesses) to offer different ordifferentiated levels of services based on the content of theapplication data or transaction information.

In this particular example, two servers (S3 and S4) have been allocatedto handle the highest dollar purchase orders. Thus, by specificallyallocating greater resources (e.g., two or more servers as compared tojust one server) for the higher dollar amount purchases as compared tothe lower dollar purchases, an e-business operating at data center 135can provide a higher level of service for purchase order messages havinga higher dollar purchase amount. In this manner, director 145 can switchor direct messages to another network device or to a specific serverbased upon a wide variety of business transaction information orapplication data.

FIG. 3 is a block diagram illustrating a director according to anexample embodiment. Director 145A includes a block 310 to determinewhether a received message includes XML data.

According to an embodiment, if the message does not include XML data,the message will be passed (e.g., directly) through to the output withlittle if any further processing by director 145A. If the message doesinclude XML data, then the message will be analyzed for making a routingor switching decision as described below.

There are many ways in which block 310 can determine whether a receivedmessage includes XML data. According to one embodiment, certain types offilenames (e.g., invoice.cgi) or filename extensions (e.g., *.cgi),which may typically be provided in the request line, may indicatewhether the message includes XML data. Thus, the filename extension maybe analyzed by block 310 to determine whether the message includes XMLdata. Other information in the message, including other headerinformation or even a particular tag in the application data itself(e.g., the <XML> start tag) can be used to identify whether or not themessage includes XML data.

According to an embodiment, block 310 is optional. However, it isadvantageous to provide block 310 where only a small percentage of theincoming messages include XML data. Without block 310, application datafor all messages will be parsed and compared to the configurationpattern, and a switching decision will be generated. Thus, for thosemessages which do not include XML data (and thus cannot be switched ordirected by director 145A), director 145A will add unnecessary latencyin the message forwarding path in the absence of block 310. On the otherhand, where a significant percentage of the messages received bydirector 145A include XML data, block 310 may be considered unnecessaryand may be omitted (because block 310 would typically add unnecessarylatency in such case).

A parser 312 is coupled to the output of the block 310 to parse theapplication data (or a portion thereof). A configuration memory 314receives and stores one or more configuration patterns or queries. Acontent based switching decision logic 316 receives the output from theparser 312 and compares the configuration patterns to the applicationdata or business transaction information (e.g., including the data andthe markup characters describing the data within the configurationpattern). The content based switching decision logic 316 then outputs aswitching or routing decision for the message on the basis of thecomparison (i.e., on the basis of the business transaction information).The configuration pattern may indicate both a pattern and a processingnode or server to process the message if a pattern is found in themessage.

The output interface 320 then switches or directs the message on thebasis of this decision (e.g., routes the message to the processing nodeor server indicated by the matching configuration pattern). For example,if there is no match, the output interface 320 may filter or block themessage, or may direct or route the message to a default server or apredetermined server in the data center 135. If a match is found, theoutput interface 320 switches or directs the message to the appropriatedestination (e.g., to the appropriate processing node or server withindata center 135).

The configuration pattern may require multiple patterns, or even ahierarchical arrangement of data elements in the application data for aspecific match. For example, the decision logic 316 may receive aconfiguration pattern that specifies:

Server IP address XML pattern S1 (e.g., 150) 10.1.1.1 From = Intel; andPurchaseAmount < $100

In such a case, the switching decision logic 316 would examine theapplication data (or XML data) to first identify a From tag that is setto Intel. Next, it would examine the transaction information to identifya PurchaseAmount that is less than $100. If both of these are found,this indicates a match.

If a match is found between the business transaction information and thepattern, the content based switching logic 316 outputs a switchingdecision to a output interface 320. The switching decision may, forexample, indicate that a match was found and identify the processingnode or server (e.g., by address and port number or other identifier)where the message should be directed.

According to an example embodiment, the decision logic 316 provides anIP address and port number to be used as a new destination IP addressand destination port number for the message. The output interface 320may then translate the destination IP address and port number in thepacket or envelope of the received message from the original destinationIP address and port number (i.e., the IP address and port number of thetraffic manager 140 or director 145A) to the new destination IP addressand port number provided by the decision logic 316. According to anembodiment, the new destination IP address identifies a processing nodeor server (e.g., within data center 135 or elsewhere) and the newdestination port number identifies a program or application on thatprocessing node or server that will receive and process the message.

The message (e.g., with its associated TCP and IP headers translated ormodified to include the new destination address and port number) is thenoutput from the director 145 and traffic manager 140. Switch 165receives the message, and then routes the message to the appropriateprocessing node or server based on the IP address.

According to an example embodiment, a client (e.g., a server 110,computer 120, etc., FIG. 1) that sends a message first establishes aconnection (e.g., a TCP connection), and then sends the message via HTTP(or other transport) to the traffic manager 140 and/or director 145A.The director 145A then parses the XML data, and makes a switchingdecision based on the business transaction information in the message ascompared to one or more configuration patterns. A new connection is thenestablished between the director 145A or traffic manager 140 and thedestination processing node or server. The message is then directed orrouted from director 145A to the specified node or server.

FIG. 4 is a block diagram illustrating a traffic manager according toanother example embodiment. Traffic manager 140 includes a securityaccelerator 415 for encrypting outgoing messages and/or decryptingincoming messages received from the network. According to an embodiment,the security accelerator 415 is a Secure Sockets Layer (SSL)accelerator, available from Intel Corporation. The security accelerator415 allows the security related tasks such as encryption and/ordecryption to be off-loaded from the application server to theaccelerator 415 of the traffic manager 140.

Traffic manager 140 also includes a director 145B and a broker 410. Adecrypted message is received by broker 410 from security accelerator415. According to an example embodiment, broker 410 operates as both anoutput interface (similar to output interface 320) and a load balancerto balance or adjust the traffic among one or more of servers orprocessing nodes within the data center 135.

Director 145B is similar to director 145A but may not include block 310and/or the output interface 320 of director 145A (as these functions maybe provided by the broker 410 in FIG. 4). Parser 312 (which may beoptional) parses the XML data. The content based switching decisionlogic 316 compares the configuration patterns to the application data orbusiness transaction information in the message and then outputs aswitching decision to broker 410 for the message on the basis of thecomparison. The switching decision output to broker 410 may, forexample, identify the IP address and port number of the selectedprocessing node or server or application server that should receive themessage.

Broker 410 performs address translation on the header(s) for themessage. The address translation performed by broker 410 includes adestination address and destination port translation and an optionalsource address and source port translation. The destination address andport translation may be performed by translating the originaldestination IP address and port number of the received message (whichmay identify the broker 410) to the IP address and port number of thespecified processing node or server (or of the specified server resourceor program). In addition, the broker may also translate the source IPaddress and port number in the packet or envelope from the originatingclient's address and port number to the IP address and port number ofthe broker 410 (or of the traffic manager 140). The message (includingone or more translated addresses) is then output from broker 410. Switch165 (FIG. 1) receives the message and forwards the message to theappropriate server based on the destination address in the message.According to one embodiment, it is not necessary to actually translatethe source IP address and port number if all return messages or repliesfrom the processing node or server are routed through the broker 410.

Broker 410 also translates destination addresses for return messages orreplies from the processing node or server sent to the client, tosubstitute the IP address and port number of the client as thedestination address and port for the return message or reply. Thus, thebroker 410 may operate as a gateway or output interface between theclient (FIG. 1) and the processing node or server, by performingdestination address translation prior to routing or forwarding themessage, and performing a similar translation for return or replymessages sent from the processing node or server back to the client.

According to an example embodiment, broker 410 and security accelerator415 may be provided, for example, as an Intel® NetStructure™ 7180E-Commerce Director. Alternatively, the broker 410 may be provided as anIntel® NetStructure™ 7170 Traffic Director. Both are available fromIntel Corporation, Santa Clara Calif. As a result, broker 410 mayperform additional functions including load balancing according to aload balancing policy or algorithm to adjust the load on each server inthe data center.

The director 145 (or 145A or B), the security accelerator 415 and thebroker 410 (or load balancer) may be provided in a network apparatus indifferent combinations, depending on the circumstances.

FIG. 5 is a block diagram illustrating another example operatingenvironment for a content based message director 145 according to anexample embodiment. As noted above, XML does not define a fixed set oftags, but rather, only defines a syntax or structured format throughwhich users can define their own set of tags or their own XML basedlanguage. In fact there are many different XML-based languages in use,each having a unique set of tags that define what elements should beprovided to comply with that XML language.

An XML language can be defined by a validation template (indicating theproper form for the tags), known in XML as a Document Type Definition(DTD). Schemas can also be used. For example, BizTalk by Microsoft Corp.includes one set of XML tags; CXML by Ariba Corp. includes its own setof tags; CBL by Commerce One includes another set of XML tags; While WML(Wireless Markup Language) defines yet another set of XML tags for thecommunication or interchange of data to and from a wireless device. Eachof these XML-based languages includes a different or unique set of tags,and thus each is generally incompatible with the other languages. Forexample, a client sending data using CXML will not be able to properlycommunicate with a processing node or server that expects to receivedata only provided according to WML.

According to an advantageous aspect of the present invention, director145 can receive an XML message, compare the application data or businesstransaction information to the configuration pattern, and then direct orroute the message (or make switching or routing decisions) to anappropriate processing node or server regardless of the type ofXML-based language used by the message. Once the director 145 isconfigured to detect or recognize one or more specific tags andcorresponding data (e.g., PurchaseAmount>$100), the director 145 candirect or route the message based on the content of the application data(e.g., based on the business transaction information provided as XMLdata), regardless of the type of XML-based language that is used by themessage.

As shown in FIG. 5, Director 145 is coupled to switch 165. There arethree sets of servers (or data centers) coupled to the switch 165,including: a set of BizTalk servers 510 (including servers 1 and 2)which communicate data using an XML based language known as BizTalk; aset of Ariba servers 515 (including servers 3 and 4) which communicatedata using the XML based language known as CXML; and a set of wirelessservers 520 (including servers 5 and 6) which communicate data usingonly the XML based language known as Wireless Markup Language or WML.These are merely provided as examples. Thus, the director 145 canoperate as a gateway or interface, receiving messages from a variety ofdifferent clients using a variety of different XML based languages, andthen directing or routing the messages to the appropriate processingnode or servers.

II. Validation Acceleration

FIG. 6 is a block diagram illustrating a network including a validationaccelerator 142 according to an example embodiment. According to anadvantageous embodiment, the data center 135 also includes a validationaccelerator 142 to pre-validate received messages before the messagesare sent to one of the application servers or processing nodes.According to an example embodiment, the validation accelerator 142 isprovided as a network apparatus. In other words, according to an exampleembodiment, the validation accelerator 142 can be coupled between anetwork 130 and a plurality of processing nodes or application servers(e.g., servers 150, 160 and 170). Providing the validation accelerator142 as a network apparatus (i.e., separate from the application servers)allows the computationally expensive task of document validation to beoff-loaded from the application servers to the validation accelerator142. Alternatively, a plurality of validation accelerators 142 may beprovided, with one validation accelerator 142 being provided for one ormore application servers or other processing nodes.

As noted above, an XML document must be checked to ensure it meets thebasic syntax and format of XML (i.e., determine whether the document is“well formed”). In addition, the XML standard also optionally allows adocument to be validated, which is a more rigorous check to determine ifthe structure or grammar of the XML document complies with structure orgrammar required by the particular XML based language. XML allows adocument to be validated against a validation template. A validationtemplate defines the grammar and structure of the XML document(including required elements or tags, etc.).

There can be many types of validation templates such as a document typedefinition (DTD) in XML or a schema, as examples. These two validationtemplates are used as examples to explain some features according toexample embodiments. Many other types of validation templates arepossible as well. A schema is similar to a DTD because it defines thegrammar and structure which the document must conform to be valid.However, a schema can be more specific than a DTD because it alsoincludes the ability to define data types (e.g., characters, numbers,integers, floating point, or custom data types). In addition, unlike aDTD (under present standards), a schema may be required to be wellformed. Thus, both the application data and the schema can both beparsed and checked for basic syntax (or well-formedness). Therefore, atleast for some applications, it is expected that schemas will possiblybecome more common than DTDs in the future.

As noted above, validating a received document against a validationtemplate is optional according to the XML standard. If a document is tobe validated against a particular validation template, the XML documentwill include validation instructions (or validation code) at thebeginning of the document. One example of validation instructions can bea document type declaration, as commonly known in XML. Another exampleis a schema (or a reference to an external schema). According to currentXML, the validation instructions (e.g., document type declaration orschema, etc.) is an optional area of the document that declares thestructure, element types, attributes, etc. of the validation template.To be a valid document, the structure and grammar of the applicationdata in the document must match the structure and grammar defined by thevalidation template (if validation instructions are included in thedocument). The validation template can be provided internal to (orwithin) the document and/or external to the document.

FIG. 7 is a diagram illustrating an example message according to anexample embodiment. The example message shown in FIG. 7 includes an XMLdocument 710. XML document 710 includes XML application data 720 (e.g.,including business transaction information) and validation instructions715.

The application data 720 is the application data that will be processedby an application server. The application data 720 may include, forexample, business transaction information, such as a list items to bepurchased, prices, quantities or other specific details of a transactionor a request for information (e.g., request for stock quote, transactiondetails).

According to an embodiment, the presence of one or more validationinstructions 715 indicates that the document can (or should) bevalidated before processing the application data 720 based on avalidation template provided within and/or identified by the validationinstructions 715. In other words, according to an embodiment, thepresence of validation instructions may indicate that the applicationdata should be pre-validated at a network apparatus (such as validationaccelerator 142) before passing the data to an application server forfurther processing. To indicate to the application server that thedocument (or the application data) has been validated, the validationinstructions may be removed from the document and/or an indication (suchas a comment or instruction in the data or a field set in the message)may be provided to indicate that the application data or message hasbeen validated (i.e., pre-validated). According to current XML, documentvalidation is optional (e.g., by the application server), even whenvalidation instructions 715 are present. However, it is possible that inthe future, validation (in XML or other languages) may be required.

If the document should be associated with a validation template(document type definition, schema, etc.) for document validation (i.e.,to allow document validation), the document will typically include oneor more validation instructions 715. The validation instructions 715provide or identify the validation template (or document typedefinition) which defines the document structure and grammar (e.g.,elements, attributes) to which the application data 720 of document 710must conform. The validation template can include an internal componentand/or an external component.

In this example shown (e.g., for XML), the validation instructions 715(or validation template) are provided as a document type declaration.The validation instructions 715 begin with the DOCTYPE statement“<DOCTYPE hogsforsale . . . ” which indicates that there is a validationtemplate, which may be provided within the document (i.e., as internalcomponent 719) or provided external to the document (i.e., an externalcomponent identified as “hogs.dtd”). Therefore, in this example, thevalidation instructions 715 provide an internal component 719 of avalidation template and an external component identifier 717 identifyingan external component. The internal component 719 and the externalcomponent (not shown) together form the validation template for thisdocument (i.e., for validating the application data 720 for document710). According to an embodiment, if validation is being performed, thepresence of the DOCTYPE statement (or other validation instructions)typically will cause an application or application server to validatethe application data 720 in the message against the validation template.

The internal component 719 of the validation template defines that avalid hosgsforsale document must include the following elements: type,avg wt, quantity and price/hog, etc. This is just an example.

In this example, the identifier “hogs.dtd” identifies an external entityor file which is an external component of the validation template. Theexternal component can be located on a remote server or other locationbased on the external component identifier 717. The external componentof the validation template (identified as “hogs.dtd”) may includeadditional requirements on the structure or grammar of the applicationdata 720 of the document 710. The external component identifier 717 maybe provided as the complete address, or as a relative address or pointer(e.g., relative to the address or location of the source or originatingnode of the message). For example, the “hogs.dtd” identifier listed inthe validation instructions 715 may actually reference the “hogs.dtd”external component 717 which may be found at (for example):oasis.xml.org/farming/livestock/hogs.dtd. As noted above, examples ofvalidation templates include a Document Type Definition (e.g., for XML),a schema, etc.

FIG. 8 is a flow chart illustrating an example operation of a validationaccelerator according to an example embodiment. At block 810, thevalidation accelerator 142 receives a message. The message may be sentover any transport or protocol(s), such as Transmission Control Protocol(TCP), File Transfer Protocol (FTP), Simple Mail Transfer Protocol(SMTP), Wireless Application Protocol (WAP, which may be used to sendand receive information with wireless devices), Hypertext TransferProtocol (HTTP), etc. The general teachings and the operation of theinvention are not dependent upon any particular transport or protocol,but rather are transport-independent.

At block 815, a validation template is obtained by the validationaccelerator 142 for validating the document or message (e.g., forvalidating the application data 720 in the document 710, FIG. 7). Thismay include first determining if validation instructions are present inthe document or message. If no validation instructions are present, thenvalidation will not be performed. If validation instructions arepresent, the validation accelerator 142 then determines whether thevalidation template for the document is provided as an internalcomponent and/or an external component based upon the syntax of or oneor more statements in the validation instructions 715.

If the validation template is provided within the document (i.e., as aninternal component), the validation template is parsed from or separatedfrom the remainder of the document. If the validation instructions 715provide a external component identifier 717, then the validationaccelerator 142 then retrieves or obtains the external component (e.g.,from a remote server or node).

At block 820 of FIG. 3, the validation accelerator 142 validates atleast a portion of the message (e.g., validates the application data720) by comparing the structure and grammar of the application data 720to the structure and grammar defined or required by the validationtemplate.

At block 825, if the document or message is valid, the validationaccelerator 142 then removes the (preferably all of the) validationinstructions, including any statements that might cause the document tobe validated (e.g., a DOCTYPE statement), any internal component(s) ofthe validation template and any references or identifiers to externalcomponents of the validation template.

At block 830, the validated document (with the validation instructionsremoved) is then sent to an application server or other processing nodefor processing.

Alternatively (or in addition to removing the validating instructions),an indication can be added to the message indicating to the applicationserver that the application data or message has already been validated(i.e., pre-validated). This pre-validation indication can be provided,for example, as a field in the message, as an instruction or comment inthe application data itself, or using another technique. For example, Inthe XML specification, besides element tags, and data, there issomething known as a processing instruction tag which provides an“escape hatch” to allow information specific to an application to beembedded in an XML document. Processing instructions are not consideredto be part of the character data content of an XML document, but theyare always passed on to the XML application by the parser. The format is<?. . . ?> for the processing instruction tag. Thus, according to oneembodiment, after the validation instructions (or the DTD or schema orreference thereto) has been removed, the following comment orinstruction tag could be added near the beginning of the document (orother location): <?validated by intel?>.

By pre-validating the document and then removing the validationinstructions from the document (and/or adding a pre-validationindication to the document or message), the expensive step of validationis off-loaded from the application server to a network apparatus,network appliance or other system (which may be referred to, forexample, as the validation accelerator 142).

FIG. 9 is a block diagram illustrating a network apparatus according toanother example embodiment. According to an example embodiment, networkapparatus 905 may include one or more of the blocks shown in FIG. 9. Forexample, in addition to the validation accelerator 142, a networkapparatus 905 may include a security accelerator 415, a content basedmessage director 145 and/or a load balancer 950. Alternatively, all fourof the components can be provided in a network apparatus 905, or anysub-combination thereof.

III. Scalable Network Apparatus

In some instances, a single validation accelerator 142 may not be ableto handle validation functions for all incoming XML traffic. In suchcases, two or more validation accelerators 142 can be cascaded togetheror (e.g., connected in series) to accommodate increased traffic. FIG. 10is a block diagram illustrating an example scalable network apparatusincluding multiple validation accelerators 142 according to an exampleembodiment. In the example network apparatus 1005 shown in FIG. 10,there are three validation accelerators 142 which are cascaded together(e.g., connected in series): validation accelerators 142A, 142B and142C. Validation accelerator 142A is coupled to the output of thesecurity accelerator 415. Validation accelerator 142B is coupled to theoutput of validation accelerator 142A. And, validation accelerator 142Cis coupled to the output of validation accelerator 142B. While threevalidation accelerators are shown in FIG. 10, any number can be cascadedtogether to provide a validation accelerator having increased capacity(or improved ability to accommodate higher traffic loads).

Likewise, in some cases a single content based message director 145 maynot be able to handle the parsing and switching (or directing) of allincoming messages (e.g., of all incoming XML messages). In such cases,two or more content based message directors 145 can be cascaded together(or connected in series together) to handle increased traffic. FIG. 11is a block diagram illustrating an example scalable network apparatusincluding multiple content based message directors according to anexample embodiment. As shown in FIG. 11, a network apparatus 1125includes several content based message directors 145 which are cascadedtogether, including message directors 145A, 145B and 145C. Similar tovalidation accelerators 142A-C of FIG. 10, the three content basedmessage directors 145A-C of FIG. 11 are cascaded or connected in seriesbetween a security accelerator 415 and application servers 1 and 2.While only three message directors 145 are shown in FIG. 11, any numberof content based message directors 145 can be cascaded together.

The operation of the network apparatus 1005 (FIG. 10) and networkapparatus 1125 (FIG. 11) will now be briefly describe. Note that thefollowing description applies generally to both the validationaccelerators 142 of FIG. 10 and the content based message directors 145of FIG. 11, except where some specific differences are noted. Theaccelerator 142 and the director 145 will both be generally referred toas a network unit.

Each network unit (e.g., each validation accelerator 142 or messagedirector 145) includes a spillover feature that can be enabled. When thespillover feature is enabled, the network unit determines whether it canprocess an incoming message based on some loading criteria. If it canprocess the message, the message is parsed and then processed (i.e.,pre-validated for accelerator 142 and directed or routed for director145). If it cannot process the incoming message based on the criteria,then the message is passed to the next network unit (accelerator 142 ordirector 145) in series, typically without parsing or processing theapplication data.

There are many different ways in which a loading criteria can bemeasured. For example, the accelerator 142 or message director 145 maydetermine if it can process the incoming message within a predeterminedtime limit, or determine whether sufficient resources (e.g., processingcapacity, memory) are presently available at the network unit to processthe message, or determine whether the traffic load (or the processedtraffic load) at the network unit has exceeded a threshold. In onesimple embodiment, the network unit determines whether it is “busy” orwhether it can process the received message. If it is “busy,” themessage is simply passed (unprocessed) to the next network unit. If theunit can process the message (i.e., not “busy”), then the network unitprocesses the received message.

The traffic load can be dynamically measured, for example, on aper-connection basis or on a per -packet or per-message basis, and thenused to determine which messages should be parsed and processed (i.e.,either pre-validated or directed), and which messages should simply bepassed to the next network unit (or passed to the application server ifthe unit is last in series). For example, if the number of connectionrequests or number of active connections with the network unit exceeds athreshold, then all further received messages (which are associated withother connections) will be passed onto the next network unit, until thenumber of connections decreases to less than or equal to the threshold.Alternatively, if the traffic load is measured on a per-packet or aper-message basis, then when the number of messages being processed orwaiting to be processed at a network unit exceeds a threshold, then allfurther messages will be passed to the next network unit, until thenumber of messages being processed or waiting to be processed decreasesback to the threshold or less than the threshold. According to yetanother embodiment, received messages are placed in a queue at a networkunit to await processing at the network unit. The messages are removedfrom the queue after being processed (e.g., either validated or routed).When the queue at the network unit reaches a predetermined level offullness, the subsequent messages are then passed onto the next networkunit until the queue decreases below the predetermined level offullness.

A more sophisticated load balancing type algorithm (such as round-robin)can be employed at one or more network units. For example, if there aretwo network units cascaded together in a network apparatus, the firstnetwork unit can automatically pass every other message (or messagesassociated with every other connection) onto the second network unit inattempt to share the traffic load more evenly across the availablecascaded network units.

According to an example embodiment, the security accelerator 415 listensor detects messages (e.g., packets) on a specific port number (e.g.,port number 443) where encrypted messages will be received. After beingdecrypted, the message is then output (decrypted or “in the clear”) on adifferent port number (such as port number 80, which indicates HTTPmessages for example). Several security accelerators can also becascaded together, which cases, the security accelerator can also passon an encrypted message to the same destination port number (port number443) because the message is still encrypted. This will cause the messageto be decrypted by the next security accelerator 415. The decrypted isfinally output by the cascaded group of security accelerators on to thenext group of network units (e.g., either message directors 145 orvalidation accelerators 142).

The processing that goes on at each network unit (either validationaccelerator 142 or message director 145) will be briefly described. Forthe content based message director 145, the processing may include thefollowing (for example):

-   -   Determine if the message can be processed (based on the        criteria);        -   if it can be processed, then process as follows:            -   parse the application data            -   validate the message (or at least a portion of the                application data)            -   either remove the validation instructions and/or add a                validation indication (e.g., <?validated by intel?>); a                validation indication can be provided in the application                data, within a header or specific field of the message                or other location            -   subsequent network units receive the message, detect the                validation indication (e.g., in a specific field), and                then pass the message on without processing it.                For the validation accelerator 142, the processing may                include the following (for example):    -   Determine if the message can be processed (based on the        criteria);        -   if it can be processed, then process as follows:            -   parse the application data            -   compare the pattern/query to the application data (e.g.,                XML data)            -   if a match is found, then translate the source and/or                destination addresses and port numbers, and then output                the message.            -   According to an embodiment, the translated destination                address and port number in the message will not match                the source address and port number of any subsequent                network units in series, and thus, the message will                simply be forwarded or passed on; alternatively, after                processing, a value can be added to a header in the                message or packet or a value added to the application                data (or other location in the message) to indicate that                the message has been pre-processed, and thus should not                be processed again at another network unit.                The network unit (or XML box) can be for either XML                Directing or Validation acceleration. They can both use                an XML parser.                When the XML box's s spillover option is enabled, if a                given XML box (or network unit) cannot process a request                within a specified interval, the request is passed on,                not parsed, to the next XML box (or network unit) in                line.                The last XML box (network unit) on the server side can                also be enabled to spill to the server. Spillover is                performed dynamically on a connection-by-connection                basis (or by packets)

A clear advantage is the ability to scale existing XML directors and orXML validation accelerators and to allow for fail-over if one of thedevices stops working.

Another Example Logic Flow

The device will look at all incoming packets(not just connections.)

-   -   If the IP address and port number in packet headers is indicated        in a mapping then assemble the application data from one or more        packets. Hold onto the packet(s) for further processing.    -   {        -   Execute the XML parser.        -   If using XML director and a match is found (matches a            pattern/query), then convert the matching IP and port pair            to the destination IP and port pair and send the converted            packets to the next network processing node (next network            unit).

If using XML validation accelerator 142, just validate and then modifythe application data (remove validation instructions and/or addvalidation indication to data) and send the converted packets to thenext network processing node/network unit.}

Several embodiments of the present invention are specificallyillustrated and/or described herein. However, it will be appreciatedthat modifications and variations of the present invention are coveredby the above teachings and within the purview of the appended claimswithout departing from the spirit and intended scope of the invention.

1. (canceled)
 2. A system comprising: a first message director to:receive a message written in an XML-based language, the messagecomprising application data; determine whether one or more configurationpatterns of at least one configuration pattern match the applicationdata of the message; if no configuration patterns of the at least oneconfiguration pattern match the application data of the message, selecta predetermined default application server of a plurality of applicationservers; if a first configuration pattern of the at least oneconfiguration pattern matches the application data of the message,select a first application server from the plurality of applicationservers based on the first configuration pattern; and direct the messagetowards the selected application server.
 3. The system of claim 2,further comprising a security accelerator to perform decryption of themessage before the message is passed to the first message director. 4.The system of claim 2, further comprising a validation accelerator tovalidate the message against an XML schema.
 5. The system of claim 2,wherein the selection of the first application server is further to bebased on a load balancing technique.
 6. The system of claim 2, the firstmessage director further to block an XML document when application dataof the XML document matches a second configuration pattern of the atleast one configuration pattern.
 7. The system of claim 2, furthercomprising a second message director to: determine whether one or moreconfiguration patterns of the at least one configuration pattern matchapplication data of a second message written in the XML-based language;and direct the second message towards an application server selectedbased on a match between a configuration pattern of the at least oneconfiguration pattern and application data of the second message.
 8. Thesystem of claim 7, wherein the second message is to be forwarded to thesecond message director when a spillover feature of the first messagedirector is enabled and a loading criteria is met.
 9. The system ofclaim 8, wherein the loading criteria is based on whether the firstmessage director can process the message within a predetermined timelimit.
 10. The system of claim 8, wherein the loading criteria is basedon processing capacity of the first message director.
 11. The system ofclaim 8, wherein the loading criteria is based on a traffic load of thefirst message director.
 12. The system of claim 8, wherein the loadingcriteria is based on a predetermined number of active connections. 13.The system of claim 2, wherein the application data comprises businesstransaction information describing at least a portion of a transactionto occur with the selected application server.
 14. At least one machinereadable storage medium having instructions stored thereon, theinstructions when executed by at least one processor to cause a firstmessage director to: receive a message written in an XML-based language,the message comprising application data; determine whether one or moreconfiguration patterns of at least one configuration pattern match theapplication data of the message; if no configuration patterns of the atleast one configuration pattern match the application data of themessage, select a predetermined default application server of aplurality of application servers; if a first configuration pattern ofthe at least one configuration pattern matches the application data ofthe message, select a first application server from the plurality ofapplication servers based on the first configuration pattern; and directthe message towards the selected application server.
 15. The medium ofclaim 14, the instructions when executed by at least one processor tofurther cause a security accelerator to perform decryption of themessage before the message is passed to the first message director. 16.The medium of claim 14, the instructions when executed by at least oneprocessor to further cause a validation accelerator to validate themessage against an XML schema.
 17. The medium of claim 14, wherein theselection of the first application server is further to be based on aload balancing technique.
 18. The medium of claim 14, the instructionswhen executed by at least one processor to further cause the firstmessage director to block an XML document when application data of theXML document matches a second configuration pattern of the at least oneconfiguration pattern.
 19. The medium of claim 14, the instructions whenexecuted by at least one processor to further cause a second messagedirector to: determine whether one or more configuration patterns of theat least one configuration pattern match application data of a secondmessage written in the XML-based language; and direct the second messagetowards an application server selected based on a match between aconfiguration pattern of the at least one configuration pattern andapplication data of the second message.
 20. The medium of claim 19,wherein the second message is to be forwarded to the second messagedirector when a spillover feature of the first message director isenabled and a loading criteria is met.
 21. The medium of claim 20,wherein the loading criteria is based on whether the first messagedirector can process the message within a predetermined time limit. 22.The medium of claim 20, wherein the loading criteria is based onprocessing capacity of the first message director.
 23. The medium ofclaim 20, wherein the loading criteria is based on a traffic load of thefirst message director.
 24. The medium of claim 20, wherein the loadingcriteria is based on a predetermined number of active connections. 25.The medium of claim 20, wherein the application data comprises businesstransaction information describing at least a portion of a transactionto occur with the selected application server.
 26. A system comprising:a plurality of application servers; and a first message director to:receive a message written in an XML-based language, the messagecomprising application data; determine whether one or more configurationpatterns of at least one configuration pattern match the applicationdata of the message; if no configuration patterns of the at least oneconfiguration pattern match the application data of the message, selecta predetermined default application server of a plurality of applicationservers; if a first configuration pattern of the at least oneconfiguration pattern matches the application data of the message,select a first application server from the plurality of applicationservers based on the first configuration pattern; and direct the messagetowards the selected application server.
 27. The system of claim 26,wherein the selected application server of the plurality of applicationservers is to perform a transaction specified by the application data.28. The system of claim 26, further comprising a security accelerator toperform decryption of the message before the message is passed to thefirst message director.
 29. The system of claim 26, further comprising avalidation accelerator to validate the message against an XML schema.30. The system of claim 26, wherein the selection of the firstapplication server is further to be based on a load balancing technique.31. The system of claim 26, the first message director further to blockan XML document when application data of the XML document matches asecond configuration pattern of the at least one configuration pattern.32. The system of claim 26, further comprising a second message directorto: determine whether one or more configuration patterns of the at leastone configuration pattern match application data of a second messagewritten in the XML-based language; and direct the second message towardsan application server selected based on a match between a configurationpattern of the at least one configuration pattern and application dataof the second message.